论文部分内容阅读
董荣森渠东剑11.(江苏卷)如图4,在平面直角坐标系xOy中,点A(0,3),直线l:y=2x-4.设圆C的半径为1,且圆心在l上.(2)若圆C上存在点M,使得MA=2MO,求圆心C的横坐标a的取值范围.赏析本题题目平和,小巧玲珑,表述简捷明了,又辅助以图形.多考了基础,少考了技巧;多考了想,少考了算;多考了方法,少考了套路.一改近几年解析几何题目运算量过大的情况,更加注重对解析几何基本思想方法的考查,考查的不仅是数形结合思想,而且是解析几何作为变量数学的开始,常用的动态分析的观点,即研究曲线必须从动点轨迹开始.
DONG Dong-Sen Drainage East Sword 11. (Jiangsu Volume) As shown in Figure 4, point A (0,3), a straight line l: y = 2x-4 in a Cartesian coordinate system xOy. Let the radius of the circle C be 1, l on. (2) If the circle C there is a point M, MA = 2MO, find the center of abscissa a range of values. Appreciation of the title of the topic of peace, small and exquisite, simple and clear, and assisted with graphics. Based on the test less skills; more than the test, less test count; test more ways, less test a routine. A few years to change the analysis of geometric problems over the amount of operation, pay more attention to analytical geometry of the basic ideas and methods Examining not only the idea of combining numbers and shapes, but also the starting point of analytic geometry as the starting point of mathematical mathematics, and the commonly used dynamic analysis point that the research curve must start from the point trajectory.